Computer



Aug. 20, 1957 E. H. B. BARTELINK ETAL 2,803,320

' COMPUTER mad sept. 14. 1945 r 4 sheets-sheet 1 INVENTORS EVERHARD H. B. BARTELINK Y 1 VIILLOUGHBY OADY www E/vavae.

ATTORNEY A118- 20, 1957 E. H. B. BARTELINK ETAL 2,803,820

AUS 20 Y1957 E. H. B. BARTELINK ETAL 2,803,820

COMPUTER Filed Sept. 14, 1945 4 Sheet's-Sheet 3 s l g O gr O m l\ r N N v 2 S lo 2 'd' 53 o. In/ l n In t o lm S2 Q LL. |l l l N nl n.

l l E 5 f2 N u 5" m N IJ INVENTORS EVERHARD H B. BARTELINK BY WILLOUGHBY M. CADY ATTORNEY Aug. 20, 1957 E.`H. B. BARTELINK ETAT.A 2,803,820

' COMPUTER l Filed Sept. 14, 1945 4Sheets-Sheet 4 74 Op 5,4 2,5 97, sa` ,cONTAcT F |G 6 99 sELsYN ||s\ Hgms l ||5\ v L MOTOR PuLsE INOlcAToR l s 'I8 /nl GENERATOR S PIP sELsYN GENERATOR 85jJ MOTOR '49 1N VEN TORS EVERHARD H. B. BARTELINK WILLOUGHBY M. CADY @Jef-4W... E ALOE/e.

ATTORNEY United States Patent Oiilice 2,803,820 Patented Aug. 20, 1957 COMPUTER Everhard H. B. Bartelink, Cambridge, and Willoughby M. Cady, Belmont, Mass., assignors, by mesne assign ments, to the United States of America as represented by the Secretary of War Application September 14, 1945, Serial No. 616,384 14 claims. (cl. 343-13) This invention relates to a mechanical computer and more particularly to a mechanical computer adapted for use with airborne radio object-locating equipment.

, As is well known in the art, the direction of flight and time of fall of a bomb released from an aircraft in flight will be affected by the altitude, velocity, and direction of flight of the aircraft, the direction and velocity of the wind, and the trail which is determined by the ballistic characteristics of the bomb. AThe term bomb, as used in this specification, should be understood to mean any missile. The ballistic characteristics Vwill remain substantially constant for any type of bomb, but the other conditions that affect the bomb as it falls may vary for each target and each tactical mission.

Resort has been had to certain expedients heretofore in order to compensate for the altitude and velocity of the aircraft, velocity and direction of the wind, and for the` trail of the bomb so that the direction and position of the aircraft for releasing the bomb with respect to the target can be predetermined. One method of computing the release point which has been tried requires quite a long ight of the aircraft preceding the release of the bomb because with this method the aircraft must remain on a constant course While the release point is being calculated. By release point is meant a theoretically determined point in space with respect to the target at which the bomb must be released to strike the target. It is sometimes dicult to get the aircraft on the correct course due to the drift of the aircraft by the wind, and the direction of flight must be altered until a correct course of flight is established.

It would be more desirable to have a computing device which enables the aircraft to take any necessary evasive action up Vto a very few seconds before the time of the bomb release. In the past enemy ghters have followed the aircraft on a bombing mission and attacked when the aircraft had to quit evasive action to get on their course preceding the bomb release. The ground controlled enemy antiaircraft fire has also been directed to the area near the bomb release point where the aircraft goes into straight flight to the release point.

` An object of the present invention is, therefore, to provide an improved computer which when associated with airborne object-locating equipment will make the necessary corrections so that the release point will be established for releasing bombs from an aircraft.

A further object is to provide a novel computer that will select a release point and permit the aircraft to take evasive action up to a few seconds before the bomb release.

For a better understanding of the invention, together with other andfurther objects thereof, reference is had to the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a vector diagram which relates the release point to the target in three dimensions; p

Fig. 2 is a modified vector diagram relatngthe release point to the target in the same plane;

Fig. 3 is a perspective view of thecomputer with sections of the frame cut away;

Fig. 4 is a partial plan view of the computer;

Fig. 5 shows certain drum calibration curves used to determine the distance of llight of a bomb due to the velocity of the aircraft;

Fig. 6 is a block diagram of the electrical connections used with the computer; and

Fig. 7 is a diagram showing a presentation as displayed on the indicator for determining the release point.

To facilitate an understanding of the present invention, the fundamental trigonometry of the problem will be discussed before an explanation is made of the computer.

Referring now more particularly to Fig. l, there is shown the geometric principles which are involved in the present invention.

In constructing the vector diagram which shows the relation of the bomb release P to the target P, a coordinate system is assumed to be fixed in the air mass 10 above the ground 11 on which the target P is located. It may be further assumed that the coordinate system moves in respect to the ground 11 in the direction of and with the Velocity W of the wind. The aircraft will have an air speed V in the air mass 10. The altitude H and air speed V of the aircraft is known so that the time of fall if of the bomb may be determined. At the moment of release of the bomb the aircraft will be at the release point P', and the bomb will travel with the air speed V through the air mass 10. The wind drag or trail T will gradually decrease the speed of the bomb in a direction opposite the air speed V. During the time of fall tf, the bombs would travel a horizontal distance V'tf if there were no trail T. The horizontal distance that the bomb will travel in the air mass 10 due to the velocity of the aircraft is (V-tf-T) which is represented in direction and magnitude by the vector OQ. During the time of fall tf, however, the whole air mass 10 will have drifted over the ground 11, moving the bomb with it by an amount equal to W-tf which is represented in direction and magnitude by the vector QP. Therefore, the total resultant horizontal distance or ground range Rw will be the vector sum of (Vif-T) and W-tf which is represented by the vector OP. The vector OP represents the altitude H of the aircraft at the release point and the vector PP represents the resultant slant range between the release point P' and the target P. The vector diagram described above could be set up in a scale model, but the model would require considerable space with the greater portion of this volume vacant. It can be seen from Fig. 1 that the correct solution may be determined if the heading angle 0 and a corrected ground range Rw are initially known. The heading angle 6 is the angle between a vertical plane passed through the release point and the target and the direction in which the aircraft must be headed at the release point to correct for wind drift of the bomb when the bomb is released from the aircraft. The heading angle 0 and the ground range Rw are determined on the ground plane. The slant range PP is determined in a vertical plane through the release point P and the target P. By making the calculations in the sequence outlined above, a solid geometry problem has been reduced to two plane geometry problems. Each solution may be made in any plane desired.. Therefore, -for simplicity and conservation of space the same plane may be used as shown in Fig. 2.

To solve the triangles for the desired information, the i following data may be set to scale: the altitude vector H, the air speed times time of fall minus trail vector (V'tf-T) and the wind vector Wtf. The vector (Vtf-T) is used as the reference direction since this greatly simplifies the problem. The wind vector W-tf may be set` in the direction of the wind. The resultant yvector PP represents distance from a target to the re- .point for the.bombiheoretica11yim strike the target.

A scale model mechanical triangle solver lmay be constructed for calculating the necessary infomation to Y establish a release point with respect'to la target and furnish the correct heading of the aircraft asV will be described with reference to Figs. 3 and 4, in which there is shown a mechanical computer which includes a frame 15 for supporting the mechanism.

An aircraft velocity vector driving meehanism comprises a shaft 16 supported by the frarne 15 onbearings 17, 178 and 19.V The portion of the shaft 1.6' between the bearings 17 and 1S is threaded and passes through a tapped heed 2.1 Se that when ythe shaft 16 ts mated in either direction, the tapped head 21 will be moved longi tvsirtelly .in either .direetien along a guide' red 2.2. The guide rod 22 is supported on either end by the frame 15. A handwheel 2-5is mounted on the end of the shaft 16 fer-'mentally rotating the 'theft 16 fer adjusting the position` of thehead 2.1 along the guidefrod 2 2. A

Y pinion gear 26 is mounted on the shaft 16 near the handwheel 25, and' a gear 27V is suitably attached to 'adrum Z9 for meshing withV gear 2.76. The drum 29 is` mounted tothe frame 175V in such'arnanner that it will be turned by the gear 2 6 as the shaft 16 is rotated. The drum, .219 het plotted en ,its Surfeee curves such as shown in Fig. which are based on the ballistic characteristics of thebomb and the velocity of the aircraft. By applying the altitude of the aircraftl along the abcissa; the velocity .of the aircraft times the time of fall minus trail (V'tf.-T) may be set directly by rotation of shaft 16` and by `observing through a window 30 in the frame 15. A diiferent set of curves will be required for eachl type of bomb that has different ballistic characteristics. y

vAn altitude adjustment mechanism comprises a shaft 3,2 Supported by en angle breeket 3l Hand Wheel 34 is mounted on one end of the shaft 32 and a bevel gear 35 is mounted on the other end, The hand wheell 34 andall other hand lwheels referred tqo in this specicatien Kleed fer adjusting the Positief; 0f apparatus will have associated with them a calibrated dial or other obvious typelof indicating devicek for use in determining the Proper QeStien ef thehend wheel for e desired p0- Stien. et thel apparatus, The geer- 3.5 meshes with e gear 36 which is supported by a` bearingv 3,7'.` The bearing 3,7 iS meente@ enthe frame- 15. A threaded Shaft V38 is supportedby an angle bracket 39 and a tapped sliding` member 4t). rlhe anglev bracket 39 is rigidly attached toanaltitude arm 41and the sliding member 40` is associatedwith the altitudearm 41 by a guide 42 that rides in a slot v43 for guiding the sliding member 40 longitudinally of the altitude arm 41. The threaded shaft 38 is associatedon oneend with the sliding mem` ber 40 through a tapped opening andhassuitably mounted on the other end a bevel gear-45 which meshes with gear 36. By rotating the hand-wheel 34,` the threaded shaft 38 will be driven by the group ofV gears 35, 36, and 45, moving they sliding member longitudinally of the altitude arm- 41.V A gear 46 is'mounted to the shaft 32 to mesh with a gear 47 which issuitably connected to a potentiometer 48. Thel potentiometer 48 is mounted in the frame and furnishes avoltage to vary the sweep voltage to correct for different' altitudes asA will be describedv later. AAV potentiometer 49I which is mounted` on the sliding member 40 furnishes` @voltage that is proportionalito the slantnrange between the release point and the target. The voltage from the potentiometer is;

variedgasa rack 50is moved longitudinally and turns a pinion gear. 51 suitably attachedtothe potentiometer 49, y or as the'position ofsliding member-40 ischang'ed, which.

. 4 t will vary the position of the potentiometer 49 with respect to the rack 50. i Y A wind velocity mechanism comprises a slotted shaft 60 supported by a bearing in the angle bracket 61 and a bearing in the frame 15. A worm gear 62 is tted over the slotted shaft 60 and is engaged thereto by means of a guide that rides in a slot on the shaft 60 for sliding longitudinally therewith. The position of the worm gear 62 on the slotted shaft 60 is controlled by a U-shaped frame 63 that is rigidly mounted to the head 21 and moves therewith. A shaft 65 has mounted on the lower end a gear 66 for meshing with the worm gear 62 and lon the top enda bevel gear 67. A threaded shaft 68 is supported on one end by the upright portion of'the wind arm 69 which will be described later and has a bevel gear 70 attached thereto for meshing with the bevel gear 67. The threaded shaft 68 is associated with a sliding support 71 through a tapped/hole therein. `The sliding support 71 is associated with the wind arm 69 by means of a guide, not shown, which rides in a slot.

72 therein so that the' sliding support 71 will move longi- )tudinally of the wind arm- 69. The'rack 50 is attached to. the slidinglsupport 71 by means ofY a Vrack guide 7-3 which will move longitudinally of the wind arm 69 with` the sliding support 71. Y A handwheel 74 is mounted on theY shaft760 and `when rgotatedtfwill, by theemeansfdescribed above, move the sliding member 71 longitudinally of the wind arnir69v.- i i A wind direction mechanism comprises a shaft 75,1

supportedbya bearing inl'the frame 15 and adifferential 76.V The shaft 75 is associated with the diierential76, preferably through suitable gears,rin such -a lmaenner as to transmit mechanical energy to a slotted shaft 77 which passes through a worm gear 78 and isv supported on the .other end by thel angle bracket 61. The worm gear 78 is engagedwith the slotted-shaft 77 by means of a guide that rides in a slot in the shaft 77 to rotate therewith.

A U frame 79 is attachedk tothe head121 for sliding theA worm gear Vtherewith longitudinally of theV shaftv 77. Af

is identified by the trade name Selsyn and receives itsV voltage from a Selsyn generator controlledby a compass. A hand wheel 86 is` mounted on the other end of the` shaft 75 and the rotation of the hand Wheel 86 or the Selsyn motor will drive.- the' differential 76 which drives thetshaft 7-7. The rotationof` the shaft 7:7 through thewormgear 78,the gear 81` and the shaftv80-will move` the-wind'tarm .69' about the axis of theshaft 80 ina plane perpendicular to thatraxis.

A resultant groundrange arm 90 is-y rigidly attached to the altitude'arm 4.1' at an angle of- 90 in thetsame plane so-.that` they movetogether about -an` axis 91 whichV is perpendicular to` that plane; The. resultant ground range arm 90 has a slot 9,2 in. which. the-guide 73'may slide. A disk 9,3 isi associated with the ground range arm. 90 and the altitude-arm 41 combination by the` shaft` 94 to rotate therewithabout the, axisf9'1'. A1 gear 95fis suitably mountedbelow the disk 9,3: to rotate when driven by means of a'pninion` gear-*96.whichV is ciine'ctedfto VtheV rotor of al Selsyn motor- 97. The Selsyn'motor V97 receives, itsvoltage from a- Selsyn generator soV connected4v to the antenna of the associated radio objcc'telocating equipment that the` gear95 rotates in` synchronisrrrwithY the` antennaof the. radio. objectflocating.equipment.`

A cam 9 8z is rigidlyV attached tolgear. 95fito actuate'av microswitch 99 which is. rigidly, attached to the diskn 93"V on eachrrevolution thereof., .Ther micro-switch 99jfi1rnishes an electrical voltage,to=the,.indicator,.each timeit is actuated by `thefeam, 9.8'. to. provide. Aznheading marker signal as will be descripedilateref.;` f f g Reference is now made to Fig. 6, which is a block diagram of the electrical system.

The wind direction system comprises a compass 102, preferably a flux gate compass, associated with the aircraft. The compass 102 controls a Selsyn generator 103 as indicated by the dotted line 104. The Selsyn generator 103 furnishes a voltage to the Selsyn motor 85 through an electric line 105. The Selsyn motor 85 is mechanically connected as described heretofore to the wind arm 69 `and will, from a voltage furnished by the Selsyn generator 103, maintain the wind arm 68 in substantially the same direction as the direction of the wind as the aircraft changes direction with respect to the wind. The Selsyn system is `not explained in detail since it is well known in the art.

A heading marker system comprises a Selsyn generator 107 mechanically connected to an antenna 108 of the radio object-locating equipment as indicated by the dotted line 109. The Selsyn motor 97 rotates the gear 95 as described heretofore in accordance with the voltage furnished by the Selsyn generator 107 through an electric line 110. Asshown more clearly in Fig. 3, for each revolution of the gear 95, the cam 98 contacts the microswitch 99 which impresses a voltage on the heading pulse generator 112 through an electrical line 113. The Voltage impressed by the micro-switch 99 will cause the heading pulse generator to send an electrical signal through an electrical line 114 which will illuminate one or more marker traces on an indicator 115. Preferably the indicator 115 is of the type known as PPI (plan position indicator).

A bomb release circle system comprises the potentiometer 49 which will impress a voltage on a pip generator 117, through an electrical line 118, which is proportional to the slant range between the target and the release point. The pip generator 117, through the electrical line 119, produces a pip which will occur at such times to generate on the indicator 115 a bomb release marker circle 127, Fig. 7, whose radius is a function of the slant range.

For a description of radio-object-locating-system indicators and associated marker circuits, reference is had to section IX, pages 252-284, of Radio System Fundamentals, Navships 900,017, published by the Bureau of Ships, Navy Department in 1944.

A variable sweep voltage curve system may be used with a hyperbolic sweep generator. The system comprises a potentiometer 48 associated with the altitude adjustment mechanism as described heretofore. The potentiometer 48 furnishes a voltage to a hyperbolic sweep generator 121 through an electrical line 122. The voltage applied to the sweep generator 121 varies the initial slope of the hyperbolic curve in accordance with the altitude of the plane so that the targets will appear on the indicator in their true positions with respect to the ground plane. For an example of a hyperbolic sweep generator, reference is had to the copending application of I ack H. Irving, Serial No. 570,412, led December 29, 1944, now Patent No. 2,611,126, dated September 16, 1952.

Referring to Figs. 3 and 4 of the drawing, the operation of the computer will be described. It has been assumed that the velocity of the aircraft, trail of the bomb, altitude of the aircraft, and wind Velocity and wind direction will be predetermined by means which are well known in the art and furnished to the operator. As has already been explained, the rotation of the hand wheel will `adjust the position of the tapped head 21 longitudinally of the shaft 22. This adjustment varies the distance between the points O and Q, Figs. 2 and 4, and represents the velocity of the aircraft times the time of fall minus trail of the bomb (V'tf-T). As indicated in Fig. 7

6 may be turned to a position where the (Vif-T) will be indicated and at the same time be set in to scale and represented by the distance between the points OQ in Figs. 2 and 4.

The rotation of the hand wheel 34 will adjust the sliding member 40 longitudinally of the altitude arm 41. This adjustment varies the distance between the points O and P', Figs. 2 and 4. By means of a calibrated dial (not shown) associated with the hand wheel 34, the anticipated altitude of the aircraft at the bomb release point may be set in and will be represented to scale by the distance between the points O and P in Figs. 2 and 4.

The wind velocity and direction of the wind at the altitudes at which 'high altitude bombing is doneremains constant over fairly large areas. The wind velocity may be set in by rotating the hand wheel 74 to a position indicated on a calibrated dial (not shown) which indicates the wind velocity anticipated at the release point times time of fall Wtf. The rotation of the hand wheel 74 will adjust the position of the sliding support 71 longitudinally of the wind arm 69. The distance between the points Q and P, Figs. 2 and 4, represents the scale value of Wtf.

The line 4between the points O and Q which is (V-tf-T) may be used as a reference and the direction from O to Q may be considered as the heading of the aircraft. The angle p which is the angle between the heading of the aircraft and the direction of the Wind may be adjusted by rotation of the hand wheel 86 for any particular direction of the wind with respect to the heading of the aircraft. As heretofore described, the rotation of the hand wheel 86 rotates the wind arm 69 about an axis in a plane perpendicular to that axis. This adjustment may be made by reference to a calibrated dial (not shown) associated with the hand wheel 86 to the position for setting in the desired angle qb.

The setting of the wind arm 69 is maintained substantially constant with respect to the anticipated wind direction at the release point as the aircraft changes course with respect to the wind direction. As the aircraft changes heading with respect to the ground, which will be the same as with respect to the wind direction, the compass 102, Fig. 6, will drive the rotor of a Selsyn generator 103 so that the Selsyn generator 103 will impress a voltage on the Selsyn motor proportional to the change in direction of the course of the aircraft. The Selsyn motor 85 will drive the wind arm 69 changing the angle qs substantially the same angle as the change in heading. Therefore, the wind arm 69 is maintained at :a substantially constant direction with respect to the anticipated wind direction at the release point and the angle will at all times be maintained substantially the angle between the heading of the aircraft and the anticipated wind direction.

lt will now be shown how the slant range PP release point P and heading of the aircraft OQ may be taken from the computer and presented on an. indicator for predetermining the release point for any set of conditions.

As described above, the disk 93 is rigidly attached by the shaft 94 to the resultant ground range -arm 90 to rotate therewith about the axis 91. The micro-switch 99 is rigidly mounted to the disk 93 so that it moves simultaneously with the resultant ground range arm 90. The cam 98 which is rigidly attached to gear 95 makes contact with the micro-switch 99 on each revolution of the gear about the axis 91. The gear 95 repeats the antenna position and is driven by the antenna Selsyn combination 108, 107, and 97.

It may be rst assumed that the wind velocity at the release point is zero which would reduce the angle 0 to zero. In this case the heading of the aircraft would be in a vertical plane through the aircraft and the target. On each contact with the cam 98 and micro-switch 99, a Voltage is impressed on the heading pulse generator 112. The heading pulse generator 112 will send an electrical signal which will illuminate a trace 125 on the indicator 115 :as shown in Fig.A 7. The trae 125 represe'ntsY the desired heading-of the Vaircraft oni-the 'indicator 1515i If a quantity equal to the wind velocity'mnltipli'ed by the? time -of fall, Wirf, is cran-lied into the Y'computerg an angle will be set in between the line OQ and-a resultant ground range arm 90 or the line between O and P; The micro-switch 99 .will be moved with the resultant the release. point will be described later.

-As has been described, to compute therrelease point the'al'titude (V-tf-T) and W-tf` may be set up lin trianglesto scale for -values anticipated at the release point preceding the approach to the target. y heading of the aircraft with respect to the wind direction is'M fed .automatically and will automatically adjust the slant range and the heading angle to compensate for the wind direction. The resultant heading angle and slantrangemay be mechanically solvedfrom the triangles and-converted into electrical presentations astraces on the indicator.

--Referring -to Fig. 7, the 4the slant range is represented by the radius of the trace or release circle 127 and the required heading at the release point is represented by the trace or heading marker 126.

When the aircraft comes into the range of the radio object-locating equipment with respect to the target, as is well known in the art the .target indication 128 will appear on the indicator 115. The aircraft may take evasive action as it nears the target and as the target indication moves in toward the center of the indicator. It -is necessary that when the target indication crosses the release circle that the operator have the aircraft headed in suchadirectio-n with. respect to the target that the target indication 129, the heading marker 126, and the release circle.127 coincide. If the wind direction and velocity andthe aircraft velocity and altitude were accurately determined before computing the release point, the aircraft would ltheoretically be at the point P shown in Fig. l when the coincidence on the indicator, as described above, takes place.

Itgis obvious, that the aircraft Vmay approach the target from ,any direction ,and the only requirement is that at the release circle the aircraft be headed at an angle with respect to the target to compensate for the wind velocity and Adirection which is represented on, lthe indicator by the heading marker.

' A principal advantage of the present invention herein disclosed is that it provides a novel mechanical computer for useV with the radio object-locating equipment to determine a release point for releasing bombs from an aircraft in such a manner that it enables the aircraft to take evasive action up to a Vfew seconds before the bomb release.V v

. Another advantage of the improved mechanical computer herein disclosed is that it can be constructed; to replace existing apparatus without requiring additional space or replacing any of the major units. However, it

will .be understood that the present invention is not to be limited to this particular use. l j

. While there. has beenr described `what is at present considered the preferred embodiment of the invention, it will be `obvious to thoseskilled-inihe artthatva-rious changes and modifications -may be made -therein without departing from the spirit of the invention.

iWhat-isclaimed is: Y Y. Y l. VIn combination withl anaircraft and a radioA objectlocating equpmenthaviug at least an: indicator,'a sweep,

generatingfcircuit, a pip generator circuit. and ia compass;

' a mechanical bomb release pointcomputer comprisinga Any changes in Y fixed pivot meansya first movable pivot nieaiisjfirst.'ad-

justing means communicatingwith said fixed pivo'tmeans; and said first movable 'pivot means vfor adjusting ,thedis-f,

tance between said fixed and first movable pivot means in accordance with the velocity of the raircraft and time',

of fallofthe bomb and'corrected for-'the trailV of-the bomb, said first adjusting meansbeing so adapted that a line through said first movable and said xed pivot" means is fixed relative to an axis of the aircraft; second movable pivot means; third movable Vpivot means; `supy porting means mounted on said fixed pivot,means `and free to move thereabout, said supporting means being' adapted to support said second andthirdginovable `pivot means, said supporting means being further vadapted to maintain said second' and third movable pivo'tfirieansjv such that a linethrough said fixedpivot meaiis'andvs'aid; second movble pivot means is perpendicular tol a line` through said fixed pivot means andvsaid third movable` pivot means, and .being still further adapted to permit radial movement of said second` and third movable pivot -m-eans; second adjusting means communicating with said secondjmovable pivot means and said supporting.

means for adjusting the distance between said` fixed pivot means and said .second Virirwablepivot means inV accordance with the altitude of the aircraft; a'lirst potentiometer means communicating with said lsecond adjusting means and connected to the sweep generating circuit in `such a manner as` to vary the output thereof tothe indi-fl andthe compass for maintaining air-angle between a` i line connecting said first and third movable pivotgmeansV and a line connecting said fixed and first movable pivot means substantially equal to the langle between theV wind direction and the aircraft direction; second potentiometer means rigidly attached lto said second movable pivot means; means communicating with said third'movable pivot means and the movable portion of said second potentiometer means for adjusting said second potentiometer means in accordance with the calculated slant range of the aircraft from its target, said potentiometer connected` to the pip generator circuit'to vary the output thereof.

for providing a bomb release circle onthe indicator in accordance with the calculated slant range to the target;vk

and means for generating a heading markerv at such a time as to produce aftrace on the indicator at an angle with respect to the aircraft direction substantially equal to the angle between a line through said first movable pivot means and said fixed pivot means and a line through said third movable pivot means and said fixed pivot-V means whereby the coincidence of said heading marker,

said bomb release circle and the target indication indi cates the correct bomb release point.

2. A mechanical computer for computing the rela` tionship between a first vector having a given magnitude and lying in a given reference direction, a second vector having a given magnitude and disposed at a given angle with respect to said reference direction, and a third vector having a given magnitude and disposed at a right angle with respect to the resultant of said first and second vec tors; said computer comprising a fixed first member have ing a pivot point, a movable second member havingwa pivot point, means for maintaining the position of the pivot point of said second member ona line lying in said reference direction and passing 'through the-.pivot point of said first mernber, means for adjusting the dis,-` tance between the pivot points of said first and second members in accordance with a given proportion of the magnitude of said first vector, a longitudinal third member pivotally mounted on the pivot point of said second member, means `for rotating said third member so that said third member assumes said given angle with respect to said reference direction, a fourth movable member having a pivot point mounted on said third member, means for adjusting the distance between the pivot points of said second and fourth members in accordance with said given proportion of the magnitude of said second vector, a fifth member having first and second arms disposed at right angles to each other, said fifth member being pivotally mounted at the apex of said arms on the pivot point of said first member, said first arm extending to and coupled to the pivot point of said fourth member in a manner such that vsaid fourth member pivot point is capable of movement along the length of said rst arm, a sixth member having a pivot point movably mounted on said second arm, means for adjusting the distance between said sixth-member-pivot point and said first-member-pivot point in said given proportion to the magnitude of said third vector, whereby the distance between said fourth-member-pivot-point and said siXth-member-pivotpoint is equal to said given proportion of lthe resultant of said first, second, and third vectors.

3. A computer, according to claim 2, further comprising a longitudinal seventh member pivotally mounted on said fourth member pivot point, said seventh mem- .ber extending to said sixth member pivot center, rotatable means pivotally mounted on said sixth member pivot center, said seventh member being effective in turning said rotatable means in response to a change in the magnitude of the resultant of said rst, second, and third vectors, and means for indicating the angular position of said rotatable means whereby the resultant. of `said first second, and third vectors is determined.

4. A computer according to claim 3 further comprising means for measuring the angle included between the first arm of said fifth member and said reference direction, said means including an element coupled to said fifth member and angularly positioned by the movement thereof, and means responsive to said element for effecting an indication.

5. A computer according `to claim 2 further comprising means for measuring the angle included between the first arm of said fifth member and said reference direction, said means including an element coupled to said fth member and angularly positioned by the movement thereof, and means responsive to said element for effecting an indication.

6. A mechanical computer for computing the relationship between a first vector having a given magnitude and a given reference direction, a second vector having a given magnitude and forming a given angle with said reference direction, and a third vector having a given magnitude and forming a fixed angle with respect to the resultant of said first and second vectors; said computer comprising a first mechanical linkage triangle having adjustable parameters for effecting a summation of said first vec-tor and said second vector to obtain a first resultant as a function of the side of said first triangle opposite said given angle, said first mechanical linkage triangle being so constructed that the magnitudes of said first and second vectors and the included angle lbetwe-en them are each independently variable; and a second mechanical linkage triangle having adjustable parameters, wherein said aforementioned side of said rst triangle is common to said second triangle, for effecting a summation of said first resultant and of said third vector, to obtain an ultimate resultant of said first, second, and third vectors as a 4function of that side of said second triangle disposed opposite said predetermined angle.

7. A computer as defined in claim 6 further including means for indicating the magnitude of the said resultant of said firs-t, second, and third vectors, said indicating 10 means including an element, connected to the side of said second triangle constituting said ultimate resultant.

8. A computer as defined in claim 7 further including means for measuring the angle included between said first vector and the resultant of said first and second vectors, said means including an element attached to that side of said first triangle constituting said first resultant and angularly positioned by the movement thereof, and means responsive to the angular position of said element for effecting an indication.

9. A computer as defined in claim 6 further including means 'for measuring the angle included between said first vector and the resultant of said first and second vectors, said means including an element attached to that side of said first triangle constituting said first resultant and angularly positioned by the movement thereof, and means responsive to the angular position of said element for effecting an indication.

l0. A device for the indication of a bomb release point comprising a first triangular member having adjustable sides and adjustable included angles, means to adjust one side of said member to a length proportional to the air speed of an aircraft times the time of fall of the bomb less the trail of the bomb, means vto adjust a second side of said member to a length proportional to the wind speed times the time of fall of the bomb, means to adjust the included angle between said sides equal to the angle between wind and aircraft directions, thereby obtaining the third side of said member, a second triangular member having one side equal to said third side of said first member, means to adjust a second side of said second triangular member to a length proportional to the altitude of the aircraft, the included angle between the third side of said.

first member and the second side of said second member being equal to thereby determining the third side of said second member, means to establish a trace on an indicator of a radio object locating device differing from a reference aircraft direction by an angle which is equal tothe angle between said first and third sides of said first triangular member, means to establish a circle on said indicator having a radius proportional to .said third side of said second triangle whereby the bomb release point is determined by the coincident occurrence of said trace, said circle and the target indication on said indicator.

l1. An apparatus for indicating a bomb release point comprising in combination with a radio object-locating device having an indicator, a first triangular member having adjustable sides and adjustable included angles, means on said member for adding a first vecto-r representing that component of the horizontal distance traversed by a falling bomb due to the velocity of an aircraft to a second vector representing that component of said distance due to the Wind velocity to obtain a resultant vector for computing the angle between said first vector and said resultant vector at which the aircraft must head with respect to a target in order that a bomb released at the proper point will strike the target, means for generating and applying a radial marker to said indicator at an angle with respect to said aircraft heading which is equal to the angle between said first vector and said resultant vector, a second triangle member having adjustable sides and adjustable included angles providing means for adding said horizontal resultant vector to a vector representing the height of said aircraft for computing the slant range to the target at the release point, and means for generating and applying a circular marker having a radius representing said slant range on the indicator of the radio object-locating device whereby the appearance of the desired target on the intersection of said radial marker and said circular indicator indicates the desired release point.

12. A device for indicating when an aircraft has reached a bomb release point comprising a cathode ray indicating tube, target locating means operable to cause a plan position indication of the location of said target withl respect to. saidiaircraft to appear on the face of said. tube, a computer intorwhich known information relative to aircraft altitude, bomb velocity and Vwind,V velocity may be fed, saidcomputer'yielding` a iirst output proportionall to the slant range of thextarget, and a second output proportional to the heading angle between the direction of flight and a vertical plane containing; the target and said bornb vrelease point, means Vto describe a bomb release circular trace on the face of said tube, said circular rtrace having a radius proportionalin magnitude to the magnitude ofY said second output, means to describe a radial heading Aline on the face of said indicator, said radial heading, line havingl anangular displacement proportionaljto-said heading angle whereby.thecalculated heading and location of the aircraft at they calculated bombrelease,pointy will be indicated whennthc plan po-l sitionindicatilonfof. said target, the bornb7release circular trace and saidrradial heading line coincide on the faceof said indicator. '11;13. A,pdevice for indicating Awhen into which known information relative to aircraft altitude,

, bomb velocity and wind velocity may be fed, said com-4 puter yielding a first output proportional to the slant;

range .of thetarget, and a second outputV proportional to the headingangle between the direction of liight anda vertical plane containing the target and said bomb. release, point,.means to describe a bomb release circular trace on, the face of said indicating device, said circular tracefhaving.

a radius proportional in magnitude to the. magnitudeV of said second output, lmeans to describe a radial headingV line on the face' of said indicating device, said radial heading line being indicative of the heading of the aircraft and having an angular displacement proportional to said heading angle so that at the time the indicatio'nrof lsaidkv target crosses said bomb release circular trace the calculated bomb release point will be indicated if the aircraft is then heading in a direction such that the radialheading line passes through the indication of said target.

p an aircraft has` reached a bomb release point comprising an indicating device, target locating means operable to cause a plan posi-` tion Vindication ofA said target with respect to said aircraft toA appear on the face of saidindicating device, a computer,

12 14; A mechanical computer comprising a frame, a pair of, arms having a fixedangular relationship therebetween pivoted to. saidk fr .anie at, a li'rst pivoLmeans, for rot-ation about 'the `ititersectioiigfsaid ,pai'rofarhas in a plane con.-. l

tainingjeach arm, a Qsecndvi'arm, means toY rotate said second a'rmaboutasecond pivot means on said frame in a plane paralleltovthe plane of rotation of said pair of arms, means to; adjust thedistance along a fixed line between saidiirst and second pivot means, one of said pair of armsintersecting said' second arm at a third pivot means, and means to adjust the distance between Vsaid second and third pivot means whereby the distance between said first and third pivot means measuredI on the first' of said pair of arms represents' the resultant of a lirst triangle determined by the distance between the first and second pivot means, the distance between the second and third pivot"` means and the angular adjustment of said second arm, ay fourth pivot means, means to move said fourth pivot vmeansalong the' secondy ofv said pair of arms whereby the distance between saidthird and fourth pivot means represents the resultant o f a second triangle Vdetermined vby theresultant ofsaid first triangle, the distance between said first and fourthypivot means and the ixed included angleA 25' betweenV said v pair-,oi arms.

`References, Cited the` file of this patent UNITED STATES PATENTS 

